About
Hypericum tetrapterum, square-stalked St John's wort, is an erect, perennial to 70 cm with distinctive, four-winged, square stems. A British native wildflower common on damp grassland and river banks, producing domed clusters of yellow flowers to 1 cm across from late summer to early autumn.
About the genus
Hypericum, the St John's worts, are annuals, perennials, shrubs or trees, evergreen or deciduous, with usually paired leaves and showy, five-petalled, yellow flowers with prominent stamens, followed by capsular or berry-like fruits. An enormously versatile genus for sun and shade in well-drained soils.
Plant details
Suggested usesBedding, containers, hanging baskets.
Care notes
CultivationPlant out after last frost in fertile, well-drained soil.
PruningDeadhead regularly to prolong flowering.
PropagationGrow from seed sown in spring.
Pest resistanceGenerally pest-free. Monitor for common garden pests.
Disease resistanceGenerally disease-resistant. Ensure good air circulation.